Outlet valve-diaphragm assembly



April 5, 1949. D. P. SMITH OUTLET VALVE DIAPHRAGM ASSEMBLY Filed June 28, 1945 /N\ ENro,c- 'DOA/AL 0 P. SM 771 47- TOANE v! Patented Apr. 5, 1949 UNITED STATES PATENT OFFIQE OUTLET VALVE-DIAPHRAGM ASSEMBLY Donald P. Smith, Cambridge, Mass.

Application June 28, 1945, Serial No. 601,979

1 Claim. 1

The invention described herein may be manufactured and used by or for the Government, for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to an outlet valve-diaphragm assembly.

An object of this invention is the provision of a valve for a gas mask which is constructed so as to permit voice transmission.

A further object of this invention is the provision of a voice transmitting valve assembly which is readily assemblable, is durable and does not have a tendency to leak.

In accordance with this invention, the outlet valve-diaphragm assembly is secured to a valvediaphragm case which in turn may be suitably secured to the face piece of a gas mask adjacent the mouth of the wearer. The valve-diaphragm case is provided with an opening over which is positioned a voice transmitting diaphragm. The diaphragm is positioned between the mouth of the wearer and the opening in the diaphragm case and a flexible valve disc is associated with the opening in order to permit exhaled air to flow around the diaphragm through the opening in the gas mask. The valve disc seats tightly to prevent entrance of air through the opening during inspiration.

For a more complete understanding of this invention reference will now be made to the accompanying drawings wherein:

Fig. 1 is a plan view of the outlet valve-diaphragm assembly constructed in accordance with one embodiment of this invention and viewed from a position near to the mouth of the wearer;

Fig. 2 is similar to Fig. 1 except the locking tongues on the guard are shown in the locked position;

Fig. 3 is a detailed, partial sectional view taken along the line 3'3' of Fig. 2;

Fig. 4 is a sectional view of the device taken along the line 4'4' of Fig. 2; and

Fig. 5 is a sectional view taken along the line 5'5 of Fig. 2.

Referring now to the drawings, the outlet valvediaphragm assembly comprises a valve diaphragm case Ill made of plastic or other suitable material which is adapted to be secured to an opening in the face piece of any suitable gas mask. The case In is preferably elliptical in shape and is provided with a central opening l2. The upwardly extending flange I4 0f the case I0 is provided with a shoulder IE on which rests a mouthpiece I8, a suitable diaphragm a gasket 22, a diaphragm guard 24, a gasket 26 and a flexible valve disc 28.

The shoulder I6 is discontinuous adjacent the ends of the case 10, adjacent which latter are provided recesses 3!]. Also the upwardly extending flange 14 of the case II] is provided with slots 32 adjacent the ends of the shoulder Hi to provide means for locking the guard 24 to the valvediaphragm case Ill by means of locking tongues 34.

As will be apparent from examination of the drawings, the guard may be firmly secured to the valve diaphragm case ID by placing it over the shoulder l6 and giving it a partial turn by means of a suitable tool cooperating with the holes 36 in order to force the locking tongues 34 into the slots 32. The mouthpiece I8 is arranged firmly to hold the diaphragm 2B, the guard, the gaskets 22 and 26, and the valve disc 28 firmly in position. The gaskets ma be constructed of any suitable material. The valve diaphragm is also constructed of any suitable material, such as impregnated silk, impervious to air or other gases. The guard 2 is preferably a perforated steel sheet but may be of any foraminous material which will permit voice transmission but at the same time will protect the diaphragm 20 from objects that may inadvertently pass through the opening I 2 in the valve-diaphragm case l0.

Also clamped between the guard l8 and the shoulder 16 is a flexible valve disc 28 made of rubber or other suitable material. This valve disc has a central opening registering with the opening I2 in the case ID thus permitting ready voice transmission through the opening l2. The inner edges of the valve disc 28 normally rest on the edges of the case ll! adjacent the opening 12. A passageway for exhaled air is provided through the recesses 30 and under the mouthpiece l8 to the opening l2. This passageway is normally closed against the entrance of air during inspiration by the valve disc 28 setting on the edges of the valve-diaphragm case ll! adjacent the opening l2.

For a human outlet valve both air flow areas A and the air flow area B each should preferably exceed /2 sq. in.

It will be apparent from the above description that a valve has been provided which will readily permit voice transmission and which, at the same time, permits the ready escape of exhaled air from within the gas mask and prevents the inflow of air into the gas mask through the valve during inspiration.

It will be understood that in apparatus of this nature, involving as it does a relatively large number of parts and elements organized into different adapted to be supported in gas-tight relationship in an opening in a gas mask face piece and having a front cover portion provided with a centrally located circular opening of substantially smaller area than that of said front cover portion, said continuous flange having a discontinuous inner shoulder comprising arcuate sections diametrically opposed across the shorter dimension of said oblong case, said arcuate sections having the same radius of curvature and coincident centers of ourvature, said centers of curvature being substantially coaxial with the center of said centrally located circular opening in the case cover, an an nular shaped valve disc having an outer portion adapted to seat on said discontinuous inner shoulder and having an inner portion adapted to seat flexibly in gas-tight relationship on the inside periphery of said centrally located circular opening and a circular gas impermeable diaphragm 4 supported on said discontinuous shoulder in gastight relationship therewith, said valve disc and said gas impermeable diaphragm being spaced from said continuous flange except where adjacent said discontinuous shoulder so as to leave an exhaled air passageway commencing at the ends of said continuous flange diametrically opposed to each other across the longer dimension of said oblong case, passing under said annular valve disc and passing out of said centrally located circular opening in the case cover, said outer portion of said annular shaped valve disc being disengaged from the inside periphery of said centrally located circular opening during exhalation and being seated in gas-tight relationship therewith at all other times.

DONALD P. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,108,256 Dym Feb. 15, 1938 FOREIGN PATENTS Number Country Date 305,080 Great Britain Jan. 29, 1929 555,668 Great Britain Sept. 2, 1943 

